An electric power steering apparatus and a control method thereof are disclosed. One example electric power steering apparatus includes: a first motor, configured to provide steering assistance corresponding to rotation of a steering wheel, wherein the first motor is powered by two power supplies, and each of the two power supplies drives the first motor to generate part of the steering assistance; and a second motor, configured to provide additional steering assistance corresponding to the rotation of the steering wheel when the first motor loses part or all of the steering assistance, wherein the additional steering assistance comprises at least part of the steering assistance lost by the first motor, and the second motor is driven by one power supply coupled from the two power supplies, to generate the additional steering assistance.